Jung Han Shin

Solution processed high-performance organic thin film transistors

In order to realize the high-performance solution-processed transistors (OTFTs) on plastic substrate, it is essential to have a solution-processible organic gate insulator which can give high field-effect mobility and on/off ratio in the devices and should endure sever photolithography process. Our crosslinked gate insulator film has a good chemical resistance to electrode etchants. However, the etchant exposure of the gate insulators resulted in an increase of the off-current while keeping the on-current the same. We also demonstrate solution processed n-type OTFTs with high mobility based on the soluble derivatives of fullerene (C60) as n-type channel materials. We obtained high electron mobilities of 0.02-0.1 cm2/V.s depending on the workfunction of the source and drain metals, demonstrating that the electron injection is contact-limited. Furthermore, we fabricated n-type OTFTs by all solution deposition process including source and drain metals as well as gate insulators and organic semiconductors. These types of OTFTs can be well suited for a wide range of existing and future flexible circuits and display applications which require a simplified process and low-weight and low-cost products.